<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>

  <style>
    body{
      background-color: beige;
    }
  div{
    width: 400px;
    height: 400px;
    color:green;
  }
  
  </style>
</head>
<body>
  <div>我是主页</div>
</body>
</html>